Abstract
The conformational changes and rheological properties of soluble sarcoplasmic proteins isolated from striped catfish (Pangasius hypophthalmus), treated at various pHs (2-12), were investigated. Isoelectric point of striped catfish sarcoplasmic proteins was determined to be pH 5. SDS-PAGE of sarcoplasmic proteins treated at various pHs, showed molecular masses ranging from 11 to 97 kDa. Most sarcoplasmic proteins, regardless of treated pHs, showed a molecular mass of 43 kDa. A decrease in total sulfhydryl content was observed when the pH was shifted away from 6, indicating disulfide formation at pH lower and higher than 6. Gradual increases of S 0-ANS and S 0-PRODAN were observed as pH increased from 6 to 12, indicating the unfolding of sarcoplasmic proteins during alkaline extraction. DSC thermograms of sarcoplasmic proteins treated at pH 5-9 exhibited an exothermic transition peak, probably due to disulfide bond formation, and/or hydrophobic interactions, which was highly related to the onset temperature of G′ rising. Gel network formation of sarcoplasmic proteins did not take place at extreme pHs (<4 or >9) where proteins were highly charged while the viscoelastic properties of sarcoplasmic proteins were observed at pH 5.5-9. The highest G′ value at 90 °C was observed at pH 5.5 and 8 (P ≤ 0.05). The gel point, a temperature at which G′ = G″, increased to higher temperature as pH was shifted away from 7.
| Original language | English |
|---|---|
| Pages (from-to) | 1046-1052 |
| Number of pages | 7 |
| Journal | Food Chemistry |
| Volume | 121 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2010 Aug 15 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Food Science
- Analytical Chemistry
Cite this
Conformational changes and dynamic rheological properties of fish sarcoplasmic proteins treated at various pHs. / Tadpitchayangkoon, Panchaporn; Park, Jae W.; Yongsawatdigul, Jirawat.
In: Food Chemistry, Vol. 121, No. 4, 15.08.2010, p. 1046-1052.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Conformational changes and dynamic rheological properties of fish sarcoplasmic proteins treated at various pHs
AU - Tadpitchayangkoon, Panchaporn
AU - Park, Jae W.
AU - Yongsawatdigul, Jirawat
PY - 2010/8/15
Y1 - 2010/8/15
N2 - The conformational changes and rheological properties of soluble sarcoplasmic proteins isolated from striped catfish (Pangasius hypophthalmus), treated at various pHs (2-12), were investigated. Isoelectric point of striped catfish sarcoplasmic proteins was determined to be pH 5. SDS-PAGE of sarcoplasmic proteins treated at various pHs, showed molecular masses ranging from 11 to 97 kDa. Most sarcoplasmic proteins, regardless of treated pHs, showed a molecular mass of 43 kDa. A decrease in total sulfhydryl content was observed when the pH was shifted away from 6, indicating disulfide formation at pH lower and higher than 6. Gradual increases of S 0-ANS and S 0-PRODAN were observed as pH increased from 6 to 12, indicating the unfolding of sarcoplasmic proteins during alkaline extraction. DSC thermograms of sarcoplasmic proteins treated at pH 5-9 exhibited an exothermic transition peak, probably due to disulfide bond formation, and/or hydrophobic interactions, which was highly related to the onset temperature of G′ rising. Gel network formation of sarcoplasmic proteins did not take place at extreme pHs (<4 or >9) where proteins were highly charged while the viscoelastic properties of sarcoplasmic proteins were observed at pH 5.5-9. The highest G′ value at 90 °C was observed at pH 5.5 and 8 (P ≤ 0.05). The gel point, a temperature at which G′ = G″, increased to higher temperature as pH was shifted away from 7.
AB - The conformational changes and rheological properties of soluble sarcoplasmic proteins isolated from striped catfish (Pangasius hypophthalmus), treated at various pHs (2-12), were investigated. Isoelectric point of striped catfish sarcoplasmic proteins was determined to be pH 5. SDS-PAGE of sarcoplasmic proteins treated at various pHs, showed molecular masses ranging from 11 to 97 kDa. Most sarcoplasmic proteins, regardless of treated pHs, showed a molecular mass of 43 kDa. A decrease in total sulfhydryl content was observed when the pH was shifted away from 6, indicating disulfide formation at pH lower and higher than 6. Gradual increases of S 0-ANS and S 0-PRODAN were observed as pH increased from 6 to 12, indicating the unfolding of sarcoplasmic proteins during alkaline extraction. DSC thermograms of sarcoplasmic proteins treated at pH 5-9 exhibited an exothermic transition peak, probably due to disulfide bond formation, and/or hydrophobic interactions, which was highly related to the onset temperature of G′ rising. Gel network formation of sarcoplasmic proteins did not take place at extreme pHs (<4 or >9) where proteins were highly charged while the viscoelastic properties of sarcoplasmic proteins were observed at pH 5.5-9. The highest G′ value at 90 °C was observed at pH 5.5 and 8 (P ≤ 0.05). The gel point, a temperature at which G′ = G″, increased to higher temperature as pH was shifted away from 7.
KW - DSC
KW - Dynamic rheological properties
KW - pH
KW - Sarcoplasmic proteins
KW - Striped catfish
UR - http://www.scopus.com/inward/record.url?scp=77949488975&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77949488975&partnerID=8YFLogxK
U2 - 10.1016/j.foodchem.2010.01.046
DO - 10.1016/j.foodchem.2010.01.046
M3 - Article
VL - 121
SP - 1046
EP - 1052
JO - Food Chemistry
JF - Food Chemistry
SN - 0308-8146
IS - 4
ER -